Shielding considerations for the small animal radiation research platform (SARRP)

Area of Science:

• Medical Physics
• Radiation Oncology
• Small Animal Imaging

Background:

• The Small Animal Radiation Research Platform (SARRP) enables image-guided radiation therapy in preclinical research.
• Initial lead shielding for a SARRP enclosure proved insufficient, leading to high external radiation levels and concerns about off-target dosing.
• Federal regulations for cabinet x-ray systems necessitate adequate radiation shielding.

Purpose of the Study:

• To identify and mitigate radiation leakage from a Small Animal Radiation Research Platform (SARRP) enclosure.
• To ensure radiation levels comply with federal safety standards.
• To prevent unintended radiation exposure to research subjects outside the treatment field.

Main Methods:

• Leakage sources were identified using Kodak X-OmatV (XV) film.
• Internal radiation doses were quantified with Gafchromic film.
• External radiation levels were measured using a survey meter.
• Modifications included restricting the exit window, redesigning the collimator, adding a beam-stop, and enhancing x-ray tube shielding.

Main Results:

• Identified five primary sources of radiation leakage from the SARRP.
• Modifications reduced internal scatter by over 100-fold.
• External radiation levels were reduced to comply with federal regulations for tube potentials of 175 kV or less.
• Eliminated the risk of significant unintended radiation doses to larger animals.

Conclusions:

• Targeted modifications effectively addressed radiation leakage from the SARRP.
• The improved shielding ensures regulatory compliance and enhances safety for small animal radiation studies.
• These enhancements are simple, cost-effective, and crucial for reliable preclinical radiation research.